Multi-use loading unit

ABSTRACT

A cartridge assembly is disclosed. The cartridge assembly includes a channel and a removable assembly in releasable engagement with the channel. The removable assembly includes a cartridge body and a support plate. The cartridge body includes an engagement structure disposed adjacent a proximal end thereof. The support plate is configured to mechanically engage the cartridge body and includes an engagement structure disposed adjacent a proximal end thereof. The engagement structure of the cartridge body is configured for longitudinal alignment with the engagement structure of the support plate. The engagement structures of the cartridge body and the engagement structure of the support plate are configured to mechanically engage the engagement structure of the channel when the removable assembly is engaged with the channel.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/376,979, filed Dec. 13, 2016, which is a continuation of U.S. patentapplication Ser. No. 14/691,906, now U.S. Pat. No. 9,526,499, filed Apr.21, 2015, which is a division of U.S. patent application Ser. No.13/280,880, now U.S. Pat. No. 9,016,539, filed Oct. 25, 2011, the entirecontents of each of these prior applications are incorporated byreference herein.

BACKGROUND Technical Field

The present disclosure relates generally to instruments for surgicallyjoining tissue and, more specifically, to a multi-use loading unit foruse with surgical instruments.

Background of Related Art

Various types of surgical instruments used to surgically join tissue areknown in the art, and are commonly used, for example, for closure oftissue or organs in transection, resection, anastomoses, for occlusionof organs in thoracic and abdominal procedures, and forelectrosurgically fusing or sealing tissue.

One example of such a surgical instrument is a surgical staplinginstrument, which may include an anvil assembly, a cartridge assemblyfor supporting an array of surgical staples, an approximation mechanismfor approximating the cartridge and anvil assemblies, and a firingmechanism for ejecting the surgical staples from the cartridge assembly.

Using a surgical stapling instrument, it is common for a surgeon toapproximate the anvil and cartridge members. Next, the surgeon can firethe instrument to emplace staples in tissue. Additionally, the surgeonmay use the same instrument or a separate instrument to cut the tissueadjacent or between the row(s) of staples.

SUMMARY

The present disclosure relates to a surgical instrument having a channeland a removable assembly disposed in releasable engagement with thechannel. The removable assembly includes a cartridge body and a supportplate. The cartridge body is configured to house a plurality offasteners or staples therein and includes an engagement structuredisposed adjacent a proximal end thereof. The support plate isconfigured to mechanically engage the cartridge body and includes anengagement structure disposed adjacent a proximal end thereof. Theengagement structure of the cartridge body is configured forlongitudinal alignment with the engagement structure of the supportplate. The engagement structure of the cartridge body and the engagementstructure of the support plate are configured to mechanically engageengagement structure of the channel when the removable assembly isengaged with the channel.

In disclosed embodiments, the engagement structure of the channelincludes raised bosses, the engagement structure of the cartridge bodyincludes a U-shaped recess, and/or the engagement structure of thesupport plate includes a U-shaped recess. In disclosed embodiments, theU-shaped recesses of the cartridge body and the support plate include aproximally-facing opening.

In disclosed embodiments, the channel includes alongitudinally-extending slot disposed adjacent a distal end thereof,and the support plate includes an outwardly-extending finger configuredto releasably engage the longitudinally-extending slot of the channel.

In disclosed embodiments, the support plate includes aninwardly-extending finger disposed on a distal portion thereof. Here,the inwardly-extending finger is configured to releasably engage agroove disposed on a distal portion of the cartridge body.

In disclosed embodiments, the support plate includes a proximalprotrusion disposed adjacent a proximal end thereof. The proximalprotrusion is configured to help prevent an actuation sled fromprematurely translating distally with respect to the cartridge body.

In certain embodiments, the channel is part of a removable loading unitthat includes an anvil assembly.

In a further aspect of the present disclosure, a loading unit for asurgical instrument has an anvil assembly, a channel, and a cartridgeassembly. The channel has a boss disposed adjacent a proximal endthereof. The cartridge assembly and anvil assembly are pivotable withrespect to one another. The cartridge assembly includes a support plate,and a cartridge body. The support plate is configured to releasablyengage the channel and includes a recess disposed adjacent a proximalend thereof. The cartridge body is configured to releasably engage thesupport plate and is configured to house a plurality of fasteners orstaples therein. The cartridge body includes a recess disposed adjacenta proximal end thereof. The recess of the cartridge body is configuredfor longitudinal alignment with the recess of the support plate. Atleast one of the recesses of the cartridge body and the support plate isconfigured to mechanically engage the boss of the channel when thesupport plate is engaged with the channel.

In disclosed embodiments, the recess of the cartridge body includes aU-shaped recess and/or the recess of the support plate includes aU-shaped recess. In such embodiments, the U-shaped recesses of thecartridge body and the support plate include a proximally-facingopening.

In disclosed embodiments, the channel includes alongitudinally-extending slot disposed adjacent a distal end thereof,and the support plate includes an outwardly-extending finger configuredto releasably engage the longitudinally-extending slot of the channel.

In disclosed embodiments, the support plate includes aninwardly-extending finger disposed on a distal portion thereof. Theinwardly-extending finger is configured to releasably engage a groovedisposed on a distal portion of the cartridge body.

In disclosed embodiments, the support plate includes a proximalprotrusion disposed adjacent a proximal end thereof. The proximalprotrusion is configured to help prevent an actuation sled fromprematurely translating distally with respect to the cartridge body.

In certain embodiments, the loading unit includes a body portion towhich the cartridge assembly and anvil assembly are attached the bodyportion being attachable to the elongate member of a surgicalinstrument.

The present disclosure also relates to a surgical instrument having achannel and comprising a cartridge assembly, a drive member and alockout mechanism. The drive member is configured to travel in a distaldirection. The lockout mechanism is configured to prevent longitudinaltranslation of the drive member. The lockout mechanism comprises a latchand a spring. The latch is disposed in mechanical cooperation with thechannel and is laterally movable from an initial position to a blockingposition. The spring is configured to bias the latch into the blockingposition in which a shaped surface of the latch obstructs the distalmovement of the drive member when the latch is in the blocking position.

In disclosed embodiments, the latch is pivotable with respect to thecartridge assembly.

In disclosed embodiments, the latch includes a hook configured to engagea portion of the drive member to prevent distal translation of the drivemember.

In disclosed embodiments, the latch includes a camming surface, andwherein when the drive member translates proximally into contact withthe camming surface, the latch pivots away from its blocking position.

In disclosed embodiments, the surgical instrument comprises a sledconfigured for longitudinal translation with respect to at least aportion of the cartridge assembly. The sled includes a tail portion thatis configured to abut a portion of the latch when the sled is adjacentits proximal-most position. The tail portion of the sled is configuredto prevent the latch from moving into its blocking position.

The cartridge assembly may include a cartridge body defining alongitudinal slot. The drive member travels along the longitudinal slotin the distal direction. The shaped surface of the latch issubstantially aligned with the longitudinal slot when the latch is inthe blocking position.

BRIEF DESCRIPTION OF FIGURES

Various embodiments of the presently disclosed surgical instrument aredisclosed herein with reference to the drawings, wherein:

FIG. 1 is a perspective view of a surgical stapling instrument without aloading unit connected thereto in accordance with the presentdisclosure;

FIG. 1A is a perspective view of a loading unit in accordance with thepresent disclosure;

FIG. 1B is a perspective view of a tool assembly of the loading unit ofFIG. 1A;

FIG. 1C is a perspective view of a cartridge assembly of the loadingunit of FIG. 1A;

FIG. 1D is an assembly view of the tool assembly of FIG. 1B;

FIG. 2 is a bottom perspective view of a portion of the tool assembly ofFIG. 1B;

FIG. 3 is a perspective view of a portion of the tool assembly of FIG.1B;

FIGS. 4 and 5 are transverse cross-sectional views of portions of thetool assembly of FIG. 1B;

FIG. 6 is a perspective view of a proximal portion of a channel of thetool assembly of FIG. 1B;

FIG. 7 is a perspective view of a distal portion of the channel of thetool assembly of FIG. 1B;

FIG. 8 is a transverse cross-sectional view of portion of the toolassembly of FIG. 1B;

FIG. 9 is a perspective view of the tool assembly of FIG. 1B;

FIG. 10 is a perspective view of a support plate of the tool assembly ofFIG. 1B;

FIG. 11 is a perspective view of a distal portion of a cartridge body ofthe tool assembly of FIG. 1B;

FIG. 12 is a perspective view of a proximal portion of the cartridgebody of the tool assembly of FIG. 1B;

FIG. 13 is a perspective view of a portion of a tool assembly of thepresent disclosure including another embodiment of a channel;

FIGS. 14 and 15 are perspective views of the channel of FIG. 13;

FIGS. 16 and 17 are perspective views of different portions of thechannel of FIG. 13;

FIG. 18 is a perspective view of a tool assembly of the presentdisclosure including a lockout mechanism;

FIG. 19 is an enlarged perspective view of the lockout mechanism of thepresent disclosure engaged with a portion of the tool assembly;

FIG. 20 is a perspective assembly view of portions of the tool assemblyincludes the lockout assembly;

FIG. 21 is a perspective view of the lockout mechanism engaged with thechannel;

FIG. 22 is a perspective assembly view of the lockout mechanism and aportion of the channel;

FIG. 23 is an assembly view of the removable assembly of an embodimentof the present disclosure;

FIG. 24 is a perspective view of a latch of the lockout mechanism of thepresent disclosure;

FIG. 25 is a perspective view of a sled of the present disclosure;

FIG. 26 is a top view of the cartridge assembly taken along line 26-26of FIG. 18 and illustrating the lockout mechanism, and the drive memberand sled in their original positions;

FIG. 27 is an enlarged view of the area indicated in FIG. 26;

FIGS. 28-31 are top views of a portion of the cartridge assembly showingthe drive member, sled, and latch in various positions;

FIGS. 32-35 are perspective views of a second embodiment of a lockoutmechanism in accordance with an embodiment of the present disclosure.

DETAILED DESCRIPTION

Embodiments of the presently disclosed surgical instrument, loading unitand tool assembly for use therewith, are described in detail withreference to the drawings, wherein like reference numerals designatecorresponding elements in each of the several views. As is common in theart, the term “proximal” refers to that part or component closer to theuser or operator, e.g., surgeon or physician, while the term “distal”refers to that part or component farther away from the user.

A surgical stapling instrument of the present disclosure is indicated asreference numeral 10 in FIG. 1. Additionally, the depicted surgicalinstrument fires staples, but it may be adapted to fire any othersuitable fastener such as clips and two-part fasteners. A loading unitfor use with surgical instrument 10 is shown in the accompanying figuresand is indicated as reference number 500. A tool assembly of the loadingunit 500 is shown in the accompanying figures and is indicated asreference number 1000.

Loading unit 500 is attachable to an elongated or endoscopic portion 18of surgical instrument 10, e.g., to allow surgical instrument 10 to havegreater versatility. Loading unit 500 of the present disclosure isconfigured for to be used more than once. In particular, the loadingunit has a removable assembly 1600 that includes the cartridge assembly1200. The cartridge assembly 1200 forms a part of the tool assembly1000, and the tool assembly 1000 forms a portion of the loading unit500. The removable assembly is configured to be removed and replaced(e.g., after firing fasteners therefrom). Examples of loading units foruse with a surgical stapling instrument are disclosed in commonly-ownedU.S. Pat. No. 5,752,644 to Bolanos et al., the entire contents of whichare hereby incorporated by reference herein. The loading unit 500 shownincludes a proximal body portion 502 that is attachable to an endoscopicportion or an elongated portion 18 of a surgical instrument 10 having ahandle assembly 12. However, the features of the loading units 500 ofthe present disclosure, including the tool assembly 1000, can beincorporated in a surgical instrument in which does not include adetachable portion of the elongated portion of the instrument.

Loading unit 500 includes a proximal body portion 502 and a toolassembly 1000. Proximal body portion 502 defines a longitudinal axis“A-A,” and is releasably attachable to a distal end of elongated portion18 of surgical instrument 10. Tool assembly 1000 includes a pair of jawmembers including an anvil assembly 1100 and a cartridge assembly 1200.One jaw member is pivotal in relation to the other to enable theclamping of tissue between the jaw members. In the illustratedembodiments, cartridge assembly 1200 is pivotal in relation to anvilassembly 1100 and is movable between an open or unclamped position and aclosed or approximated position. However, the anvil assembly, or boththe cartridge assembly and the anvil assembly, can be movable.

With reference to FIG. 1D, for example, anvil assembly 1100 includes ananvil cover 1110 and an anvil plate 1112, which includes a plurality ofstaple forming depressions 1113. Anvil plate 1112 is secured to anunderside of anvil cover 1110 and defines a channel 1114 (see FIG. 8,for example) therebetween. When tool assembly 1000 is in theapproximated position, staple forming depressions 1113 are positioned injuxtaposed alignment with staple receiving slots of the cartridgeassembly 1200.

The tool assembly includes a channel or carrier 1300 which receives andsupports a cartridge assembly and a support plate 1500. The cartridgeassembly has a cartridge body 1400. The cartridge body and support plate1500 are attached to the channel or carrier 1300 by a snap-fitconnection, as discussed below, a detent, latch, or by another type ofconnection. The cartridge assembly includes fasteners or staples 1414.Cartridge body 1400 defines a plurality of laterally spaced stapleretention slots 1410, which are configured as openings in tissuecontacting surface 1412 (see FIG. 11). Each slot 1410 is configured toreceive a fastener or staple 1414 therein. Cartridge assembly 1200 alsodefines a plurality of cam wedge slots which accommodate staple pushers1416 and which are open on the bottom (i.e., away from tissue-contactingsurface 1412) to allow an actuation sled 1418 to pass longitudinallytherethrough.

Further details of the various components of cartridge assembly 1200,including the connection between its various components, and theremovability and replaceability of cartridge body 1400 and support plate1500 with respect to channel 1300, are discussed below. Generally, theremovable assembly 1600 includes cartridge assembly 1200 and supportplate 1500. The removable assembly 1600 is removable from channel 1300,e.g., after staples 1414 has been fired from cartridge body 1400.Another removable assembly is capable of being loaded onto channel 1300,such that surgical instrument 10 can be actuated again to fireadditional fasteners or staples 1414, for instance.

Channel 1300, which may be machined (e.g., e.g., 1300 a in FIGS. 13-17)or made of sheet metal (e.g., 1300 b in FIG. 9), includes one or a pairof engagement structures or proximal bosses 1310 (e.g., 1300 b in FIG.6), a pair of cut-outs 1320 disposed adjacent a distal end, a pair ofdistal slots 1330, a central slot 1340, a pair of proximal holes 1350,and a ramped surface 1360. Proximal holes 1350 are configured to alignwith/mechanically engage a pair of corresponding holes 1120 (e.g., witha pin or protrusion extending through holes 1350 and holes 1120) onanvil cover 1110 to facilitate a pivotal relationship between anvilassembly 1100 and cartridge assembly 1200. It is envisioned thatengagement structures 1310 may be pins, protrusions, or similarstructure.

Cartridge body 1400 includes a central slot 1420, and rows of stapleretention slots 1410 positioned on each side of slot 1420 (see FIG. 11).In the illustrated embodiment, three rows of retention slots 1410 areshown. More specifically, cartridge body 1400 is configured such thatactuation sled 1418 can pass through the cam wedge slots and forcestaple pushers 1416 towards anvil plate 1112. The staples 1414, whichare supported on the pushers, are then forced out of their respectivestaple retention slots 1410. Cartridge body 1400 also includes a pair ofengagement structures or U-shaped recesses 1430 (which may, in otherembodiments, be slots or openings) adjacent its proximal end, a pair ofcentral bosses 1440, a pair of distal protrusions 1450, and a pair ofdistal grooves 1460. Pairs of upper and lower mounting surfaces 1470,1480, respectively, are disposed adjacent a proximal end of cartridgebody 1400, and are disposed adjacent respective upper and lower mountingslots 1472, 1482.

With particular reference to FIG. 10, support plate 1500 includes a basesurface 1510, a longitudinal slot 1520 extending through base surface1510, a pair of proximal fingers 1530 disposed and extendingsubstantially perpendicularly from a proximal end of base surface 1510,a pair of intermediate fingers 1550 extending substantiallyperpendicularly from a middle portion of base surface 1510, a pair ofinwardly-extending fingers 1560 and outwardly-extending bosses 1570disposed adjacent a distal end of base surface 1510, and a pair ofproximal protrusions 1580 disposed adjacent the proximal end of basesurface 1510. Each proximal finger 1530 includes an engagement structureor proximal-facing U-shaped recesses 1532, an upper mounting flange1534, and a lower mounting flange 1536. As can be appreciated, supportplate 1500 helps maintain pushers 1416 in place with respect tocartridge body 1400. Additionally, longitudinal slot 1520 allows aportion of a drive member to pass through the support plate 1500. Thedrive member may be a dynamic clamping member 1402. The dynamic clampingmember or drive member 1402 drives the actuation sled 1418 through thecartridge body 140. The central slot of the cartridge body, the centralslot of the channel, and the longitudinal slot of the support plate areall configured to align with one another to allow the passage of thedrive member.

In use, to connect cartridge body 1400 and support plate 1500, cartridgebody 1400 and support plate 1500 are assembled or brought together suchthat the proximal-most end of cartridge is positioned between proximalfingers 1530 of support plate 1500 and in contact with base surface 1510thereof. Support plate 1500 is then longitudinally translated (e.g.,slid distally) with respect to cartridge body 1400 such that uppermounting flanges 1534 and lower mounting flanges 1536 engage uppermounting slots 1472 and lower mounting slots 1482, respectively. Thelongitudinal translation between cartridge body 1400 and support plate1500 continues until a distal-most end of proximal fingers 1530 contacta respective vertical wall 1490 (FIG. 12) of cartridge body 1400. Atthis stage, U-shaped recesses 1430 are laterally adjacent and alignedwith U-shaped recesses 1532 (see FIG. 3), and continued proximalmovement of cartridge body 1400 with respect to support plate 1500 isprevented. Next, or concomitantly with the relative longitudinaltranslation between cartridge body 1400 and support plate 1500, cut-outs1552 within intermediate fingers 1550 of support plate 1500 arepositioned around central bosses 1440 of cartridge, andinwardly-extending fingers 1560 are moved into engagement with distalgrooves 1460 of cartridge. Cartridge assembly 1200 and support plate1500 comprise a removable assembly 1600, which is removable from andreplaceable onto channel 1300 by the user of the surgical instrument 10and/or loading unit 500.

Removable assembly 1600 is insertable onto channel 1300 by approximatingremovable assembly 1600 and channel 1300 such that proximal bosses 1310are positioned proximally of U-shaped recesses 1430 and 1532, and suchthat distal ends of distal slots 1330 are positioned proximally ofproximal ends of outwardly-extending bosses 1570. Next, removableassembly 1600 is translated longitudinally (e.g., proximally) withrespect to channel 1300 such that outwardly-extending bosses 1570translate proximally within distal slots 1330 until proximal bosses 1310contact U-shaped recesses 1430 and 1532. Next, or concomitantly with therelative longitudinal translation between removable assembly 1600 andchannel 1300, cut-outs 1320 of channel 1300 are moved into engagementwith distal protrusions 1450 of cartridge body 1400. Ramped surface 1360is engaged by the dynamic clamping member 1402 in order to move theanvil assembly 1100 and the cartridge assembly 1200 with respect to oneanother. A similar surface could be provided on the anvil assembly 1100,in other embodiments. It is envisioned that ramped surface 1360 may alsofacilitate the alignment and/or engagement between channel 1300 andsupport plate 1300 and/or cartridge body 1400.

Once assembled, a user is able to actuate movable handle 22 to ejectstaples 1414 from cartridge body 1400 and into tissue, as describedbelow. It is envisioned that proximal protrusions 1580, which extendfrom base surface 1510, help maintain actuation sled 1418 in itsrelative position with respect to support plate 1500 before actuation ofinstrument 10. That is, it is envisioned that actuation sled 1418, or aportion thereof, is positioned proximally of proximal protrusions 1580,and that proximal protrusions 1580 form a physically barrier to hinderany premature distal advancement of actuation sled 1418. Once a userintends to actuate instrument 10 and distally advance actuation sled1418 beyond proximal protrusions 1580, the force used to advanceactuation sled 1418 is sufficient to force a lower surface or portion ofactuation sled 1418 over proximal protrusions 1580.

After staples 1414 have been ejected from cartridge body 1400, and auser wishes to use the same instrument 10 to fire additional staples1414 (or another type of fastener or knife), the user can remove theremovable assembly 1600 by sliding removable assembly 1600 distally withrespect to channel 1300. Next, a user removes the removable assembly1600 from the channel 1300. Another removable assembly with unfiredstaples can be loaded into the channel 1300. In other embodiments, acartridge body of a cartridge assembly can be removable from a supportplate after the removable assembly is removed from the channel 1300. Thecartridge body is removed by sliding support plate 1500 proximally withrespect to cartridge body 1400. Another cartridge body, if desired, maybe coupled to the support plate and inserted into the channel.

In certain embodiments, the removable assembly is part of a loading unit500 that is removably attached to the elongated portion of a surgicalstapling instrument, such as elongated portion 18. This enables the userto choose a staple line length that is shorter or longer. It is alsocontemplated that the removable assembly can be used with a surgicalinstrument that does not have a loading unit that is removable andinstead has jaws permanently attached to the elongated portion 18.

During operation of stapler 10, actuation of its movable handle 22 willfire the staples. The handle assembly 12 has an elongate actuation shaftthat is translated distally when the movable handle 22 is pivotallymoved by the user. The actuation shaft of the handle assembly caninclude teeth that are engaged by the movable handle 22, or the handleassembly 12 can include a series of gears for moving the actuationshaft. Alternatively, the handle assembly can include a motorized driverfor moving the actuation shaft, or the handle assembly can be attachableto a separate motorized driver.

In certain embodiments, through successive strokes of the movablehandle, a drive rod 30 (a distal portion of which is illustrated inFIGS. 1 and 27-31)) is advanced distally, such that drive rod 30 pushesa portion of the drive assembly (which includes the dynamic clampingmember 1402) to translate distally through cartridge body 1400. (Furtherdetails of how actuation of movable handle 22 causes distal advancementof drive rod 30 are explained in U.S. Pat. No. 6,953,139 to Milliman etal., which is hereby incorporated by reference herein.) Distal movementof the drive assembly, and in particular, the dynamic clamping member ordrive member 1402, causes approximation of one jaw member with respectto the other. That is, an upper portion of the dynamic clamping member1402 travels through the channel 1114 between the anvil plate 1112 andthe anvil cover 1110, and a lower portion of the dynamic clamping member1402 travels below the carrier 1300 of the cartridge assembly 1200,which causes approximation of the anvil assembly 1100 and the cartridgeassembly 1200 to clamp tissue therebetween. For example, the channel1300 may have a lower surface defining a camming surface and the lowerportion of the dynamic clamping member 1402 engages the camming surfaceto pivot the cartridge assembly 1200 toward the anvil assembly 1100.

Additionally, distal translation of the dynamic clamping member 1402causes the actuation sled 1418 to move distally through cartridge body1400, which causes cam wedges 1419 of actuation sled 1418 tosequentially engage pushers 1416 to move pushers 1416 vertically withinstaple retention slots 1410 and eject staples 1414 into staple formingdepressions 1113 of anvil plate 1112. Subsequent to the ejection ofstaples 1414 from retention slots 1410 (and into tissue), a cutting edgeof the dynamic clamping member 1402 severs the stapled tissue as thecutting edge travels distally through central slot 1420 of cartridgebody 1400.

It is also envisioned, in further embodiments, that an end effector ortool assembly like the end effector or tool assembly 1000 is arrangedfor articulating between a first position where tool assembly 1000 isaligned with longitudinal axis “A-A,” and a second position where toolassembly 1000 is disposed at an angle with respect to longitudinal axis“A-A.” For example, the anvil assembly 110 may be pivotably attached tothe proximal body portion 502 of a loading unit 500, or pivotablyattached to the elongated portion of the instrument. The loading unitincludes one or more cables or linkages disposed in the proximal bodyportion 502 and attached at the tool assembly 1000. When the cable orlinkage is displaced, the tool assembly pivots and articulates withrespect to the instrument. Further details of providing articulation aredescribed in detail in commonly-owned U.S. Pat. No. 6,953,139 toMilliman et al., the contents of which has previously been incorporatedby reference in their entirety. Further, the tool assembly can beconfigured not to articulate.

Additionally, it is envisioned that instrument 10 is powered by a powersource and/or motor. Further details of such a powered surgicalinstrument are included in U.S. Patent Publication No. 2008/0255607, theentire contents of which are hereby incorporated by reference herein.

Further, and as illustrated in FIG. 11, for example, the presentdisclosure includes a cartridge body 1400 having a steppedtissue-contacting surface 1412. In such an embodiment, different sizedstaples 1414, or all the same sized staples, may be used. Furtherdetails of a staple cartridge having multiple staple sizes are includedin U.S. Pat. No. 7,407,075 to Holsten et al., the entire contents ofwhich are hereby incorporated by reference herein.

The present disclosure also relates to methods of using the describedsurgical instrument 10, loading unit 500, and tool assembly 100 toperform a surgical procedure and to methods of assembling the variouscomponents thereof, as described above.

With reference to FIGS. 18-35, two embodiments of a lockout mechanism2000, 2000 a of the present disclosure are shown. For each of theseembodiments, a surgical instrument having the lockout may have achannel, removable assembly, cartridge body, support plate, and theengagement structures discussed above. Furthermore, the presentdisclosure is directed to a removable assembly having the lockout, or aloading unit having the lockout.

With reference to FIGS. 18-31, the first embodiment of lockout mechanism2000 includes a latch 2010 and a spring 2030, and is configured toprevent re-firing of cartridge body 1400 of removable assembly 1600, andalso prevent distal translation of dynamic clamping member 1402 after aninitial distal translation of knife and prior to another removableassembly 1600 being loaded onto channel 1300.

With particular reference to FIGS. 22 and 24, latch 2010 includes a body2012 having an upper surface 2014 and a lower surface 2016, a lowerprotrusion 2018 depending downwardly from lower surface 2016, a springstop 2019 extending upwardly from upper surface 2014, and a shapedsurface 2020 on a first lateral side 2022. The body 2012 also has asecond lateral side 2024. The shaped surface 2020 has two sides. Thefirst side 2020 a is angled with respect to the central slot 1340 whenthe latch 2010 is in a blocking position in which the latch obstructsthe passage of the dynamic clamping member 1402. The second side 2020 bof the shaped surface 2020 extends transversely to the central slot 1340when the latch is in the blocking position. (See FIG. 30).

Referring now to FIGS. 19-24, latch 2010 is mechanically engaged withchannel 1300 so that the latch 2010 can pivot with respect to thechannel 1300. In particular, lower protrusion 2018 of latch 2010 (FIG.24) extends through an opening 1380 (FIG. 22) in channel 1300, such thatlatch 2010 is pivotable with respect to channel 1300. Lower protrusion2018 is maintained in mechanical engagement with channel 1300 by a lockpin 2050 (FIG. 22). Alternatively, the protrusion can be omitted and aseparate pivot pin in engagement with the body 2012 and the channel 1300can be used.

With regard to FIGS. 21-22, spring 2030 includes a first leg 2032, asecond leg 2034, and an intermediate portion 2036 interconnecting firstleg 2032 and second leg 2034. First leg 2032 is in contact with aportion of channel 1300. For example, the channel 1300 may have a slot1301, a notch, or some other feature for restricting the movement of thefirst leg 2032. Second leg 2034 is disposed in contact with spring stop2018 of latch 2010. Intermediate portion 2036 is disposed between firstleg 2032 and second leg 2034. For example, the spring may have aU-shaped configuration (see FIG. 27), or some other shape, such asL-shaped.

Spring 2030 is in mechanical cooperation with a portion of the cartridgeassembly 1200. The spring is configured to bias latch 2010 towards itsblocking position. In the initial position of the dynamic clampingmember 1402 and the sled 1418 (e.g., prior to distal advancement thereofto fire staples and incise tissue), a tail portion 1417 of sled 1418(FIG. 25) physically prevents the shaped surface 2020 of latch 2010 frommoving from its initial position into its blocking position, and thusallows distal translation of dynamic clamping member 1402 and sled 1418(see FIGS. 26 and 27). After translation of the dynamic clamping memberand sled, the spring moves the latch 2010 to the blocking position,where the shaped surface 2020 of latch 2010 obstructs the central slot1340 of channel 1300 and the longitudinal slot 1520 extending throughbase surface 1510 of support plate 1500 (see FIGS. 30 and 31), such thatshaped surface 2020 would block distal translation of dynamic clampingmember 1402 when the dynamic clamping member 1402 has been retractedafter firing staples and cutting tissue.

The latch 2010 is laterally movable from an initial position to ablocking position. The latch moves laterally, which enables the shapedsurface of the latch to obstruct the slot and move away from a positionthat obstructs the slot of the cartridge assembly.

During retraction of the dynamic clamping member, the dynamic clampingmember slides along the shaped surface first side 2020 a, keeping thelatch 2010 away from the dynamic clamping member and pivoting the latchagainst the bias of the spring. In the retracted position of the dynamicclamping member, it is disposed proximally of shaped surface 2020 andthe sled 1418 and/or tail portion 1417 is not abutting the shapedsurface 2020. The latch 2010 pivots to the blocking position, so thatthe second side 2020 b obstructs and/or prevents distal movement of thedynamic clamping member.

During distal advancement of dynamic clamping member 1402 and sled 1418,and after sled 1418 distally passes latch 2010 such that shaped surface2020 is no longer in contact with tail portion of sled 1418, dynamicclamping member 1402 abuts the shaped surface 2020, which physicallyblocks latch 2010 from moving into its blocking position, and thuspermits distal translation of dynamic clamping member 1402 (see FIG.28).

When cartridge assembly 1200 or removable assembly 1600 is removed fromchannel 1300, latch 2010 continues to block dynamic clamping member 1402(see FIG. 31). When a new cartridge assembly 1200 or removable assembly1600 is loaded onto channel 1300, tail portion 1417 of the new sled 1418engages shaped surface first side 2020 a of latch 2010 and pivots latch2010 away from its blocking position. Without a sled having the correctconfiguration, the latch remains in the blocking position.

With reference to FIGS. 32-35, a second embodiment of lockout mechanism2000 a is shown. A surgical instrument having the lockout may have achannel, removable assembly, cartridge body, support plate, and theengagement structures discussed above. Furthermore, the presentdisclosure is directed to a removable assembly having the lockout, or aloading unit having the lockout. Lockout mechanism 2000 a includes alatch 2010 a, and a spring. The spring is not shown for clarity, but maybe as discussed above. Unlike the embodiment of lockout mechanism 2000discussed above, this embodiment of lockout mechanism 2000 a does notinclude a lock pin 2050. Here, to maintain latch 2010 a in engagementwith channel 1300 a, lower surface 2016 a of latch 2010 a includes alocking member 2018 a depending therefrom.

In the illustrated embodiment, locking member 2018 a includes a pair ofparallel walls that are interconnected by a pair of arcuate walls. Theopening 1380 a of channel 1300 a includes similar, but slightly largershape with respect to locking member 2018 a and also includes a circularrecess 1381 a, around which locking member 2018 a can rotate (see FIGS.34 and 35).

To engage latch 2010 a with channel 1300 a, locking member 2018 a isinserted through opening 1380 a and latch 2010 a is then rotated apredetermined amount (e.g., about 40 degrees to about 130 degrees) suchthat latch 2010 a does not fall through opening 1380 a of channel 1300a. The spring (not shown in this embodiment for clarity) may then bepositioned between spring stop 2018 a of latch 2010 a and a portion ofchannel 1300 a, as described above.

As can be appreciated, use of surgical instrument including the secondembodiment of lockout mechanism 2000 a is similar to, or that same asuse of the surgical instrument including the first embodiment of lockoutmechanism 2000, as described above.

While the above description contains many specifics, these specificsshould not be construed as limitations on the scope of the presentdisclosure, but merely as illustrations of various embodiments thereof.Therefore, the above description should not be construed as limiting,but merely as exemplifications of various embodiments. Those skilled inthe art will envision other modifications within the scope and spirit ofthe claims appended hereto.

1. A surgical instrument, comprising: a channel including an engagementstructure disposed adjacent a proximal end thereof; and a removableassembly disposed in releasable engagement with the channel, theremovable assembly comprising: a cartridge body configured to house aplurality of fasteners therein, the cartridge body including anengagement structure disposed adjacent a proximal end thereof; and asupport plate configured to mechanically engage the cartridge body, thesupport plate including an engagement structure disposed adjacent aproximal end thereof; wherein the engagement structure of the cartridgebody is configured for longitudinal alignment with the engagementstructure of the support plate, and wherein the engagement structure ofthe cartridge body and the engagement structure of the support plate areconfigured to mechanically engage the engagement structure of thechannel when the removable assembly is engaged with the channel.